Abrasive implement



Oct. 28, 1947. C, H, RANDOLPH ABRASIVE IMPLEMENT Filed April 7, 1944Patented Oct. 28, 1947 2,429,647 ABRAsIvE IMPLEMENT Chalmers H.Randolph, St. Paul, Minn., assignor to Minnesota. Mining & ManufacturingCompany., St. Paul, Minn., a corporation of Dela- Ware Application April7, 1944, Serial No. 529,973

12 Claims. l

This invention relates to implements for employing sheeted abrasivematerial in abrading operations.

It finds particular utility in the form of implements suitable for usingabrasive tape (which may be strips of the abrasive sheet material thatis commonly calledv sandpaper) in abrading irregular and/or smallsurfaces, or for various special abrading operations.

One objective is to provide an implement which will abrade efficientlywith abrasive tape and which will itself hold a substantial supply ofthe tape in a manner to permit bringing fresh portions of tape intoabradingposition whenever the operator desires. o

Another objective is to provide such an irnplement that is compact andotherwise suitable for abrading irregular and/or small surfaces,particularly when in places that are diicult of access with ordinaryabrading devices.

Briefly, the present invention provides a device or implement comprisingva body portion having a. backing surface or presser surface adjacent towhich abrasive tape may lie when the tape is in abrading position andwhich bears or presses against the back of the tape when the tape isbeing pressed or applied by the implement against an object (aworkpiece) in an abrading operation, and a supply spindle and a take-upspindle rotatably mounted on or in the body, the said spindles beingadapted to carry rolls of abrasive tape and being loacted in relation toeach other and to the presser surface so that tape may be led from asupply roll thereof on the supply spindle to abrading position adjacentthe presser surface and thence to the take-up spindle whereby freshportions of tape may be brought into abrading position when desired,

The device described and illustrated herein as anvillustrativeembodiment of this invention is an elongated abrasive tool of a, shapeand design generally resembling that of a large screwdriver in which theflat sides of the outer tip portion or -blade provide the presser orbacking surfaces for applying the tape to a workpiece and the shankportion 1s hollowed` out to forin a magazine or chamber for holding asupplyroll and from out of which the tape is led outwardly along onesurface of the blade or fingen thence around thev outer tip thereof andthence back along the opposite side to a take-up roll in the magazine.

Figure 1 shows the described abrasive device in use.

Figure 2 is a top elevation or plan view of the finger and the magazine.

Figure 3 is a left side elevation ofthe finger and the magazine.

Figure 4 is a horizontal longitudinal sectional view of the finger andthe magazine taken on the line Ill-4 in Figure 3.

Figure 5 is a vertical cross-sectional View of the mazagine takenaxially of the forward spindle on the line 5-5 in Figure 3.

Figure 6 is a vertical longitudinal sectional View of the magazine takenon the line 6 6 in Figure 4.

Figure 7 is a vertical cross-sectional view of the forward portion ofthe magazine taken on the line 1-1 of Figure 3.

The body comprises generally the frame, housing, chamber or magazine IIand the attached presser member, blade or finger I2. The finger portionof the body carries a padding layer I3 to provide the backing or pressersurfaces I4 and I4' adjacent t6 which the abrasive tape T lies when inabrading position and which bear against the back of the tape when thetape is being pressed by the implement against an object or workpiece,such as the object I5, in an abrading operation.

A supply roll R. of the tape is mounted or wound upon the supply spindleI6 from whence the tape is led out of the magazine II through theopening Il adjacent a guide roll .or shaft I8. thence along the backingsurface or presser surface Il of the inger I2, abrasive side out, thencearound the outer end or tip of the nger, thence back along the pressersurface I4', through the magazine opening I1 adjacent the guide shaftI8' and into the interior of the magazine where it is wound up on thetake-up spindle I6' to form a roll R' of used tape.

The rollsfare xed to the spindles Iii-I6 in order that rotation of thespindles, which are suitably journaled in the side wall 24 of themagazine, will wind or unwind the tape. Knurled wheels or thumb-turnsIll-I9' are fixed to the spindles I6-I6', respectively, to provide meansfor turning the latter.

To provide braking means for holding the tape against motion during anabrading operation, two ratchet wheels 20-20 are xed on the spindlesIii-I6', respectively, each wheel having radially extending V-shapedgrooves or notches 2|-2I, respectively, near the periphery on its a sidesurface facing the wall 24. The notches are adapted to receive the pawls22-22, respectively,

which latter are xed on opposite ends of a leaf spring 23. The parts ofthe magazine are positioned so that there is a space between the 3ratchet wheels 20-20' and the side wall 24 of the magazine II toaccommodate the spring. The spring is suitably fixed at its approximatecenter to the side wall 24 and is sprung or loaded so that itsextremities or ends which carry the pawls 22--22' are pressed againstthe ratchet wheels 20-20' so that whenever a wheel 20 or 2U' turns so asto bring a notch 2| or 2I' opposite a pawl 22 or 22', the pawl willenter and be held in the notch, thereby holding the ratchet wheel andits respective spindle I6 or IB' against turning in either direction.But since the notches are V-shaped in cross-section and the pawls areheld yieldably by the spring 23, a turning impulse applied manually bythe operator to the thumbturn I9 in either direction, or to thethumb-turn I9' in either direction will unseat the pawl and thecorresponding spindle will yield to the rotating impulse of thethumb-turn, thus providing a two-direction pawl and ratchet means whichpermits the spindles to be rotated in either' direction.

The braking or holding power of the pawls and ratchets are preferablyadjusted (by suitable means or design such as depth of notches, strengthof spring, etc.) to be sufficient to hold the tape substantiallymotionless along the presser surfaces I4 and/or I4' during an abradingoperation, yet not so great but what they will release the spindlesIB--IB' in response to a turning impulse applied manually by theoperator to the thumb-turns I9 or I9' in either direction. Provision ofa padding I3 on the finger I2 to form the tape-contacting pressersurfaces I4-I4', particularly when such padding is one or more layers ofcloth or other rough surfaced material that make a good frictionalcontact with the tape backing, assists in holding the tape substantiallymotionless during anabrading operation.

The notches 2 I--2I' may be spaced from each other by any suitabledistance on the ratchet wheels 20-20, as long as they are close enoughtogether so that a notch will be opposite a pawl when a spindle hasturned to draw the tape to a desired degree of tautness along a pressersurface. One means for accomplishing this with a minimum number ofnotches is to space the notches closer together on one wheel than on theother. In the illustrated embodiment the notches 2| on the ratchet wheel20 are closer together than the notches 2I' on the ratchet wheel 20'(Figure 6). After a length of fresh tape has been positioned along thepresser surface I4 by first unwinding it from supply spindle I6 and nextwinding up the spent portion of tape on takeup spindle I 6 until theslack is taken up, the spindle I6' may then be turned to the point ofmaximum tautness for the tape along the surface I4' at which the pawl22- will engage a notch 2|', whereupon the final tightening of the tapemay then be accomplished by turning the spindle I6 to the point ofmaximum tautness for the tape along the surface I4 at Which the pawl 22will engage a notch 2I.

It will be apparent that the closer the notches are together, thegreater the degree of tautness to which the tape can be drawn and heldby the spindle with which such notches are associated. Consequently, inthe illustrated embodiment, the tape adjacent the presser surface I4 isusually more taut than that adjacent the surface I4', and the surface I4is therefore usually the preferred backing or presser surface in theillustrated embodiment. However, it is to be understood that surface I4'may also serve as a backing or presser surface; and that either spindleI6 or I6' may be the supply spindle (and the other the take-up spindle);and that either ratchet wheel 20 or 20', whether associated with thesupply or the take-up spindle, may carry the closer spaced notches. Thenotches 2I-2I' need not necessarily be V-shaped in cross-section as longas they and the pawls 22j-22 are shaped in relation to each other sothat the pawls will be unseated and will release the ratchet wheels inresponse to a turning impulse that is manually applied to the thumb-turnI9 in either direction or to the thumb-turn I9' in either direction. Ifdesired, a one-direction ratchet means may be used for a take-up spindlebut, whatever braking means is employed, it is preferable that bothspindles be rotatable in both directions whenever the operator sodesires.

In use, the device may be equipped with a handle or handles suitablyattached, as to the stud 25, and employed by applying the finger to anobject to be abraded. The illustrated embodiment is shown equipped witha vibrator 26 that is powered through a cable 21. When fixed firmly tothe stud 25 the vibrator causes the entire device, including thev ngerI2, to vibrate so that manual pressure by the operator of the linger(covered with the abrasive tape as above described) against a workpieceI5 causes the portion of the workpiece thus contacted to be abraded.

The device is thus seen to be particularly adapted to abrading small andrelatively inaccessible surfaces, or to abrading small selected areas oflarge surfaces. An extremely small area can be abraded by application ofonly the tip end of the vibrating finger thereto.

The finger I2 may be of any suitable size, shape or design as long as itprovides a presser surface over which abrasive tape may be drawn andheld taut. Or the magazine II may itself be the finger with one or moresurfaces serving as the presser surface. The word tape as used herein isa relative term, referring to sheets that are long in proportion totheir width, and the principle disclosed herein may be employed toconstruct devices for using strips or lengths of abrasive sheet materialof any width in a wide variety of abrading operations.

Various other alternatives will be obvious to those skilled in the artas usable for the carrying out of this invention without departuretherefrom; also it is to be understood that the abrasive fingerdescribed and illustrated herein is simply illustrative of thisinvention, the scope of which is defined only by the claims.

I claim:

1. An elongate abrasive implement for the application of abrasive tapecomprising an outwardly extending blade or finger which forms theforward portion of the implement, a handle which forms the rear portionof the implement, an intermediate shank portion hollowed out to form asupply magazine having suitable apertures through which the tape mayenter and leave the magazine, the longitudinal axes of the finger, shankand handle being in approximate alignment, the finger having at leastone backing surface adjacent to which abrasive tape may be laid to backthe tape when the tape is being employed to abrade an object byapplication thereto of a tape-covered surface of the nger, two spindlesrotatably mounted within the magazine, the said nger and spindles beinglocated in relation to each other, to the magazine and to the aperturestherein in such manner that abrasive tape may be led from a supply rollthereof on one spindle, outwardly through one of the apertures, alongone surface of the finger, around the end thereof, back along anothersurface of the finger, inwardly through another of the apertures intothe magazine to the second spindle, means for rotating the spindles anda braking means associated with each spindle adapted to hold thespindles fixed against turning from the pull of the tape duringVabrading operations and to release them for rotation during operation ofthe rotating means.

2. The device of claim 1 in which each braking means comprises a pawland ratchet.

3. The device of claim l in which each braking means comprises a pawland ratchet means comprising a notched wheel xed to the spindle, a pawl,and spring means for releasably holding the the pawl in a notch, thenotches on one ratchet Wheel being in closer spaced relation to eachother than are the notches on the other ratchet wheel.

4. An elongate abrasive implement for the application of abrasive tapecomprising an outwardly extending blade or finger which forms theforward portion of the implement', a handle which forms the rear portionof the implement, an intermediate shank portion hollowed out to form aSupply magazine having suitable apertures through which the tape mayenter and leave the magazine, the longitudinal axes of the ringer, shankand handle being in approximate alignment, the nger having at least onebacking surface adjacent to which abrasive tape may be laid to back thetape when the tape is being employed to abrade an object by application-thereto of a tape-covered surface of the finger, two spindles rotatablymounted within the magazine, the said finger and spindles being locatedin relation to each other, to `the magazine and to the apertures thereinin such manner that abrasive tape may be led from a supply roll thereofon one spindle, outwardly through one of the apertures, along onesurface of the nger, around the end thereof, back along another surfaceof the finger, inwardly through another of the apertures into themagazine to the second spindle, means for rotating the spindlesseparately in either direction and a braking means associated with eachspindle adapted to release them for rotation in either direction uponoperation of the said rotating means and adapted to hold the spindlesfixed against turning in either direction from the pull of the tape tohold the tape taut along the backing surface during an abradingoperation.

, 5. The device of claim 4 in which each braking means comprises atwo-direction ratchet.

6. The device of claim 4 in which each braking means comprises atwo-directional pawl and ratchet means comprising a notched wheel fixedto the spindle, a pawl, and spring means for releasably holding the pawlin a notch, the pawl and notches being shaped and positioned to renderthe pawls resistance to rotation of the wheel approximately equal ineach direction.

7. The device of claim 4 in which each braking means comprises a'two-directional pawl and ratchet means comprising-a notched wheel xed tothe spindle, a pawl, and spring means forreleasably holding the pawl ina notch, the pawl and notches being shaped and positioned to render thepawls resistance to rotation of the wheel approximately equal in eachdirection and the notches on one ratchet wheel being in closer spacedrelation tol each other than are the notches on the other ratchet wheel.

8. The device of claim 4 in which each braking means comprises atwo-directional paw1 and ratchet means comprising a notched wheel xed tothe spindle, a pawl, and spring means for releasably holding the pawl ina notch, the notches comprising radially extending V-shaped grooves onthe side of the wheel, the pawl-engaging portion of each notch beingapproximately symmetrical about an axial plane to render the pawlsresistance to rotation of the wheel approximately equal in eachdirection, and the notches on one ratchet wheel being in closer spacedrelation to each other than are the notches on the other ratchet wheel.

9. An elongate abrasive implement for the application of abrasive tapecomprising an outwardly extending blade or finger which forms theforward portion of the implement, a handle which forms the rear portionof the implement, an intermediate shank p tion hollowed out to form asupply magazine having suitable apertures through which the tape mayleave and reenter the magazine, the longitudinal axes of the finger,shank and handle being in approximate alignment, the linger having atleast one backing surface adjacent to which abrasive tape may be laid toback the tape during an abrading operation, two spindles rotatablymounted within the magazine, means for manual rotation of the spindlesseparately in either direction, and a braking means associated with eachspindle .adapted to hold the spindles normally xed, comprising a notchedWheel xed to the spindle, a pawl, and spring means for releasablyholding the pawl in a notch, the pawl and notches being shaped andpositioned to unseat the pawl and release the wheel in response tomanual pressure in either direction through the wheel-rotating means.

10. The device of claim 9 in which the notches comprise radiallyextending V-shaped grooves on the side of the wheel.

11.. The device of claim 9 in which the notches are in closer spacedrelation to each other on one wheel than on the other.

12. The device of claim 9 in which the notches comprise radiallyextending V-shaped grooves on the side of the wheel, and are in closerspaced relation to 'each other on one wheel than on the other.`

CHALMERS H. RANDOLPH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS l Date

